If this is your first visit, be sure to
check out the FAQ by clicking the
link above. You may have to register
before you can post: click the register link above to proceed. To start viewing messages,
select the forum that you want to visit from the selection below.

Thermocouples were established in different planes in a hive of wintering honey bees (Apis mellifera L.) at Madison, Wis., and temperatures were determined. Then the colony was killed with gas. Exact determination of the cluster location in relation to recorded temperatures proved that such temperature records precisely locate the cluster and show where brood is being reared, where bee activity occurs beyond the brood area, and the insulating shell of relatively inactive bees.

From 1,200,000 thermocouple temperature determinations made in beehives during the winter, the following information was obtained:
(1 of 20)

More great stuff on hive thermoregulation

Fascinating stuff. Brood nest temperatures can have huge impacts on memory and learning. The results for brood reared at cooler temps in that last study are reminiscent of some of the CCD symptoms. Perhaps as field and cluster heater bees are lost the developing larvae become less able to learn and remember thus compounding the situation.

Bees raised at 36°C performed as expected for bees typically classiﬁed as ‘‘good learners,’’ whereas bees raised at 32°C and 34.5°C performed signiﬁcantly less well. We propose that the temperature at which pupae are raised will inﬂuence their behavioral performance as adults and may determine the tasks they carry out best inside and outside the hive.

I have heard that some queen raisers slow development to suit their schedule by controlling temp. Also, in baby nucs, queen cells often get cooled below optimal temps. How important are learning abilities in queens? Does the same apply?

Useful diversion?

I guess that is more of a calorimetry question. How much stored energy in honey is converted to heat energy is per unit of time per bee when they generate these temps? What kind of "heat mileage" can a honeybee achieve per milligram of honey?

Good morning Ernie. That is a good point. Some of this data suggests to me that we may want to set the incubators a little warmer. 96.8F seems warmer than much of the published brood temps I have seen in the past.

Personally, I got an electronic indoor/outdoor electronic thermometer with a probe on a wire for $10 or so and put the probe into the brood area of various hives at various times. I found the regulation was very constant, within a fraction of a degree.

That gave me an idea of what the correct temperature was, and I used that in the incubator. I forget the exact number and could not find it just now.

Anyhow, the reason that the recommended temperatures are lower than the ideal is that most incubators do not nearly approach the beehive accuracy in regulation, and even a little overshoot on the high side can damage queen cells. Slightly lower temperatures do not have so obvious and immediate an effect. Therefore, the recommended temps is lower by safety factor.

I'd recommend using the same thermometer that you use to establish the correct temp for calibrating and monitoring the incubator, since individual units may vary by a degree or two.

If your incubator is very well regulated, the hive temperature can be used. Seems, from my experimenting, that a good, populous hive is the best incubator.

That may be true until you get a cold snap with a lot of capped cells on hand. When the cluster gets tight, the far edges can get ignored.

Considering the impact of brood temp on learning, memory, and performance a well engineered incubator with very tight tolerances on the temp controls would be a good thing when dealing with large quantities of cells.

That may be true until you get a cold snap with a lot of capped cells on hand. When the cluster gets tight, the far edges can get ignored.

That is very true. That is why we either wrapped the hives with cells in the early season or used styro boxes. With good insulation and reduced entrances, a good hive will not cluster even when the temperatures go below freezing. Also, keeping feed on continuously tends to increase activity in the hive.

Nonetheless, there are many, many subtle things that must be observed and considered when rearing queens out of the swarming season, and the danger of chilling cells in one that many people miss. They then wonder why the end cells on a bar often fail.

There are lots of reasons for using a good incubator, but a poor one can be a handicap, especially if the operator is not able to monitor it and control it properly.

As mentioned previously, too, even a good incubator can overheat if the room goes above its set temperature. Good hives can maintain their regulation even if the weather gets really hot.

I would like to see a study on queen performance and incubation temp variations, like the worker bee study referenced earlier. If the temp controller is precise and accurate it can be a handy place for lots of capped cells in a safe controlled enviro...but if the thing is not set up properly then it could be much more of a liability than an asset.

thermology/caloremetry question

So how many milligrams of honey does it take for a worker to generate that 107.5 degrees?

I would wager some equation could be developed to calculate how much honey per unit of time, a given brood volume would require, perhaps on a per bee basis. Of taking into consideration the R values of combs, wax, and such. Where are the math physics bee geeks? My old college physics book is very dusty.

I think one of those studies posted in this thread referenced an R value for established working brood comb. I suppose another consideration would be the prevailing ambient temperature.

It is amazing to me that one bee can heat up to 107.5F. This brings several questions to mind. First how much honey does it take to generate that much heat? Secondly how many bees doing this can warm how large of a brood area?

The deleterious effects of cooler brood incubation temps on learning in memory seem like they may have a role in some of the observed CCD symptoms. I suppose as field bees drop off due to heavy attrition nurse bees may be prematurely recruited to foraging and a vicious cycle sets in with the next generation of recruits hatching with already developed learning and memory problems.

I sure most seasoned beeks know how many bees it takes to cover a given amount of brood at certain ambient temps and with normal attrition rates. I just think it may be useful to quantify this, perhaps for modeling purposes.